In Patent Literature 1, there is disclosed a head mounted display (HMD) which is wearable on a head of a user and configured to display a right-eye image and a left-eye image for a right eye and a left eye of the user, respectively, to thereby provide a three-dimensional virtual space to the user. Further, in Patent Literature 2, it is disclosed that, as a method of updating a three-dimensional virtual space image in real time based on change in point of view of a user wearing an HMD, a real-time rendering method is employed.
[Patent Literature 1] Japanese Patent Application Laid-open No. Hei 8-006708
[Patent Literature 2] Japanese Patent Application Laid-open No. 2004-013326